DONETSK, Ukraine — Fighting raged Sunday on the western outskirts of Donetsk as the advancing Ukrainian army tried to seize control of the rebel stronghold. In danger of being encircled, the separatists renewed their calls for Russia to send troops to their aid.
To support their operations, the pro-Russia fighters have been confiscating vehicles and food from residents and businesses in Donetsk. The center of the major industrial city is nearly deserted, with few people or cars on the streets and most stores and restaurants closed.
A spokesman for the Ukrainian military operation, Alexei Dmitrashkovsky, said government soldiers were fighting Sunday to hold positions they had taken on the edge of Donetsk.
In the part of the city closest to the fighting, an artillery shell hit a school overnight, but no one was reported hurt.
‘‘The shell went through the roof and exploded inside the building, setting off a fire, but we still don’t know who fired it,’’ said Dmitry Levonchik, a 45-year-old coal miner. ‘‘Who needs this war? What are they fighting for?’’
The sound of gunfire and explosions was heard to the west.
Pavel Gubarev, the self-proclaimed governor of the separatist Donetsk region, said the rebels would win quickly if Russia sent troops.
‘‘Of course it would be great to see Russian peacekeepers here: strong artillery units, tank brigades,’’ Gubarev said. ‘‘This war would be over in a day, maybe two.’’
Ukraine and the West say they have evidence that Russia is arming the separatists. Russia denies this and describes the Russian citizens fighting in eastern Ukraine as volunteers.
The conflict began after the Moscow-leaning president of Ukraine was ousted in February following months of street protests, and a new pro-Western government took power in Kiev.
Alarmed by the prospect of Ukraine moving closer to the European Union and NATO, President Vladimir Putin fomented the pro-Russia insurgency in the mostly Russian-speaking east with the apparent aim of winning an agreement that would allow Moscow to maintain its influence in Ukraine, US officials say.
If he is unable to win such a compromise and the Ukrainian army continues to take back rebel-held cities and towns, Putin may come under increased pressure to intervene militarily.
Many Donetsk residents have counted on help from Russia.
‘‘What is Putin waiting for? He inspired us to fight,’’ said Ilya Sumyatin, a 38-year-old separatist fighter. ‘‘We had hoped for help from Russia, but we have been abandoned. Our strength is nearing an end and the Ukrainian army is advancing.’’
The separatist fighters in Donetsk have proclaimed the right to confiscate any ‘‘strategically important resources’’ to support their operations.
On Sunday, a major trucking company that delivers to grocery stores said it was suspending its operations in Donetsk after rebel fighters raided its warehouses. The company, Deliveri, said in a statement the goods stolen Saturday evening were worth about $840,000.
Viktor Okhramovich, who drives a minibus taxi, said the separatists seized his vehicle. ‘‘What am I supposed to do? I have nowhere to go to complain,’’ he said.
With the Ukrainian army approaching the city, many Donetsk residents have become reluctant to express support for the rebel fighters.
‘‘Donetsk has turned into a dark hole where you can be taken prisoner, robbed, killed, or have your home destroyed,’’ said Inna Statsenko, a 52-year-old bank employee, who said she once supported the separatists.
‘‘Now I see that nothing good will come of this. It’s time to escape this nightmare,’’ she said, pointing to a nine-story apartment building that had been hit by shelling.
After not seeing much fighting other than a rebel attempt in May to seize the city airport, Donetsk came under shelling last week. About 200 apartment buildings and 2,300 private homes remain without electricity, city officials said.
An estimated 200,000 people in the city of 1 million have left their homes, said Ivan Volchok, an official in the regional administration who said his department helps organize travel to safer places in Ukraine.